A memory foam mattress can provide you with a comfortable and supportive night's sleep. Made from viscoelastic foam, which is a type of high-density polyurethane foam, it will soften in response to both body heat and pressure. This gives it a unique plush feel that will hug your body as you sleep. Most memory foam mattresses are not made entirely out of memory foam though, as this would make them too soft and you would end up sinking into the bed. Instead, they usually have layers of different thicknesses and densities of foam to provide both comfort and support. They can be a great choice for side or back sleepers who need cradling support, but because they mold to your body and can trap heat, they may not be ideal for stomach sleepers who need a more breathable and firm surface. If you tend to sleep hot, you may want to avoid traditional memory foam mattresses and look for ones made with gel memory foam instead.